[P4-dev] complex function like pattern matching

yunchen chang y2924uki at gmail.com
Thu Apr 6 04:01:12 EDT 2017


Hello Andy,

Thanks for your response.

1) I am using mininet(simple_switch.cpp) to be my environment,
    so I want to know where should I implement my C/C++ code? (
primitives.cpp?)

2) Is there anything I should pay special attention to? ( like:
restrictions of compiler )

Thank you.

Best regards,
Abbie

On Mon, Apr 3, 2017 at 8:35 AM, Andy Fingerhut <andy.fingerhut at gmail.com>
wrote:

> The P4 language is focused on parsing and manipulating packet headers, not
> payloads.
>
> One could write a custom extension that could search for patterns in a
> payload, but it would be non-portable, and would have to be implemented in
> a target-specific language, e.g. C/C++ for a software model, Verilog for an
> ASIC or FPGA, etc.  It would be similar to having a library written in
> assembler and calling it from C, with the assembler implemented anew for
> each target processor.
>
> Andy
>
> On Mon, Mar 27, 2017 at 9:13 AM, yunchen chang <y2924uki at gmail.com> wrote:
>
>> Hello everyone,
>>
>> I am doing an experiment for DPI in P4.
>> (detect packet label in data plane, not in controller)
>>
>> I need some complex funtcions like lookup the host name of payload.
>> Example:
>> host_name: tw.yahoo.com
>> mtach_key: .yahoo.
>>
>> I plan to write function in "primitives.cpp" at first.
>>
>> But after I read this posted : [http://lists.p4.org/pipermail
>> /p4-dev_lists.p4.org/2016-August/000449.html], it pointed that P4 can't
>> implement "pattern matching".
>>
>> I want to know is there any solution in current P4?
>> (or any suggestion)
>>
>> Thank you.
>>
>> Best regards,
>> Abbie
>>
>> _______________________________________________
>> P4-dev mailing list
>> P4-dev at lists.p4.org
>> http://lists.p4.org/mailman/listinfo/p4-dev_lists.p4.org
>>
>
>
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